Recently many implantable devices of this kind have been provided; they are placed in the course of a surgical procedure beneath the skin tissue so that the refilling site is accessible through the skin, the catheter being implanted between the device and the particular body compartment. In this manner it is possible to selectively feed an accurate dose (also called "embolus") at the desired target with pharmacological concentrations only in that area and with negligible concentrations elsewhere; storing a plurality of emboli makes the device autonomous for several injections.
In some devices the pumps are actuated by automatic means making it possible to program the injections (electromagnetic pumps: French patent No. 2,537,440, WO patent No. 81/00888 . . . ; electric motor pumps: European patent No. 11 25 85, U.S. Pat. No. 4,447,224, French patent No. 2,354,105, European patent No. 2 50 05, thermodynamic or chemical energy pumps: French patent Nos. 2,528,313; 2,370,481; Canadian patent No. 946,696; U.S. Pat. No. 3,731,681; WO patent No. 80/01755, French patent No. 2,195,461, U.S. Pat. No. 3,692,027 . . . ; osmotic or electroosmotic pumps: French patent Nos. 2,390,177 and 2,354,106, U.S. Pat. Nos. 4,340,054, 4,300,557, 3,995,631 . . . ). However these are complex, very costly bulky and often only partly implantable devices.
Furthermore devices are known wherein the pump is manually actuated by the patient himself or the practitioner in order to inject an embolus. Illustratively the U.S. Pat. No. 4,013,074 describes a device of this type which comprises within a rigid enclosure on one hand a liquid reservoir and a gas reservoir separated by a diaphragm and on the other hand a peristaltic pump which can be manually actuated through the skin by means of a suitable mechanical system. The manually actuated devices of this type as a rule are simpler than the automated devices mentioned above; also they allow administering the drug upon demand in a much more flexible manner, which is a significant factor frequently (especially when injecting anti-plan opiates). However the known devices of this kind remain relatively complex and hence costly (for instance because of the presence of moving mechanical members in the case of the above cited device), and as a rule they bother the patient when they are implanted in the tissues, sometimes being difficult to implant or to actuate (some requiring several operations in a predetermined sequence to inject a dose).
The object of the present invention is a novel sequential feed device of the manually actuated kind and intended to be implanted in an accessible subcutaneous region in order to sequentially feed doses or emboli. Essentially the object of the invention is a device with a much simplified structure which is cheaper to produce than the known devices of this type.
Another main object of the invention is to create a device with a reservoir containing an increased number of doses in order to increase its autonomy while retaining a small bulk and a shape proper to ease its implantation.
Another object is to create a device which can be integrated into the subcutaneous tissues by adapting itself to their local shapes in order to reduce the bother suffered by the patient.
Another object is to create a device allowing easy and reliable use and capable to feed upon each pump acutation an exact and predetermined dose.
Another object of the invention is to provide the device with an auxiliary access site for the chronic injection of substances different from that contained in the reservoir (complementary drug administration, sealing check by opaqueproduct injection . . . ).
Another object is to provide a device without any danger of interference or artifacts in the course of modern imaging exploration techniques (tomodensitometry, magnetic resonance . . . ).